Electrical boxes are generally attached to a wall stud or other support structure for supporting an electrical device and enclosing electrical wiring. The electrical boxes are mounted in a variety of positions, orientations, and locations in the wall or ceiling by the use of nails, screws, or other fasteners. In new construction, the electrical box is attached to the wall stud or other support structure with the open front face of the electrical box facing outward. Generally, the open front face of the electrical box is positioned outwardly from the wall stud a distance corresponding to the thickness of the wall material or membrane so that the front edge of the electrical box is flush with the outer surface of the wall. In some forms of construction, the stud or other support structure does not allow a proper orientation of the electrical box so that the open end of the electrical box is recessed within the wall when the wall material is attached to the wall stud. This makes it difficult to mount the electrical wiring device to the electrical box while being properly oriented with respect to the front face of the wall. The electrical wiring device must be securely attached to the electrical box which often results in the wiring device being recessed with respect to the outer surface of the wall.
Renovating old construction can also create difficulties in positioning the electrical box with respect to the outer surface of the wall. The new wall board or paneling can be applied over the existing wall so that the original electrical box is recessed within the wall and spaced from the front surface of the wall. It is generally very difficult to move an electrical box within an existing wall and to reposition the electrical box without damaging the existing wall so that the front face of the electrical box is flush with the outer surface of the wall. The recessed electrical box often results in the electrical device being recessed with respect to the front surface of the wall.
Various devices have been produced that include an adjustable assembly for connecting to an outlet box that can accommodate different thicknesses of wall structures. These devices typically provide a mechanism for positioning the electrical device in a desired location with respect to the outer surface of the wall structure. These prior devices generally require a series of movable and adjustable components that are attached directly to the electrical box prior to installing the wall. After the wall is attached to the wall stud, the device is adjusted to position the electrical device in the desired location with respect to the outer surface of the wall.
An example of such a device is disclosed in U.S. Pat. No. 4,634,015 to Taylor. This device includes a plate and an open collar on the mounting plate and circling a central opening. A box frame slides within the collar to contact the side walls of the collar. The box frame is adjusted outwardly with respect to the collar by adjustment screws mounted in the box frame and connected to a frame on the collar or on the mounting plate.
Another example of an adjustable mud ring is disclosed in U.S. Pat. No. 5,931,325 to Filipov. The adjustable mud ring for the electrical box has a plate that can be attached to a conventional electrical box. The adjustable mud ring has a collar extending outwardly from the plate and a movable sleeve surrounds the collar. The sleeve is attached to the collar by screws that adjust the position of the sleeve with respect to the collar.
A further example is disclosed in U.S. Pat. No. 7,301,099 to Korcz. This device includes a base plate having a central opening and a collar encircling the central opening. A sleeve slides through the collar and is adjusted by adjustment screws extending between the sleeve and inwardly extending legs on the base plate.
Other examples of electrical box extension devices are disclosed in U.S. Pat. No. 6,820,760 and U.S. Patent Application Publication No. 2005/0051354 and 2005/0082079 to Wegner et al. The adjustable assemblies disclosed in these patents and published applications include an electrical box extension having an extending member for a switch or electrical receptacle. The extension member includes fastener brackets and a fastener base bracket. The fasteners extend through the fastener brackets of the base bracket to adjust the position of the extending member with respect to the base. Another form of adjustable extension members for electrical boxes include a base attached to the electrical box and a sleeve extending outwardly from the base plate. The sleeve can include frangible or breakable lines so that the length of the sleeve can be shortened to position the end of the sleeve in a desired location with respect to the outer surface of the wall. Examples of this type of device are disclosed in U.S. Pat. No. 2,989,206 to McAfee, U.S. Pat. No. 3,525,450 to Payson and U.S. Pat. No. 3,651,245 to Moll.
The prior devices have been generally suitable for the intended purpose. However, there is a continuing need in the industry for an improved adjustable device for mounting an electrical component to an electrical box.